In data communication systems, it is often useful to modularize interface electronics and other interface elements in a data communication module. For example, in an optical data communication system, an opto-electronic transceiver module may include a light source such as a laser, and a light detector such as a photodiode, and may also include driver and receiver circuitry associated with the laser and photodiode. To use such an opto-electronic transceiver module, an optical fiber cable is plugged into or otherwise connected to a port in the module. Such a module also includes electrical contacts that can be coupled to an external electronic system.
Another example of a data communication module is an Ethernet transceiver module. To use an Ethernet transceiver module, an Ethernet cable, which may have an electrical rather than an optical connector, is plugged into a port in the module. The module may include signal conditioning electronics. Such a module also includes electrical contacts that can be coupled to an external electronic system.
Some data communication modules are configured to be plugged into a cage or other receptacle. A standard communication module configuration commonly referred to in the art as Small Form Factor Pluggable (SFP) includes an elongated housing having a generally rectangular profile. An SFP module is pluggable into a bay in the front panel of a metallic cage having an array of such bays. In addition to serving as an interface between an array of modules and an external electronic system, the cage provides protection against electromagnetic interference (EMI). The nose end of each module includes a mechanism that latches the module in the cage. The mechanism typically comprises a pin on the module housing and a catch on the cage. As a user pushes or inserts the module into the cage, the pin engages an opening in the catch to latch the module in place in the cage. To release or delatch the module from the cage, the user flips a pivoting bail on the module or otherwise moves a mechanism on the module to cause the pin and the catch to disengage from each other. As the bail or other user-operated mechanism is more directly involved in delatching the module from the cage rather than latching the module in the cage, the mechanism as a whole is typically referred to as a “delatch mechanism.” Prior delatch mechanisms for SFP modules generally fall into two categories: moving catch and moving pin.
A moving-catch delatch mechanism delatches the pin from the catch by flexing the catch away from the pin in response to the downward motion of the bail so that the pin and catch do not interfere with each other when the module is withdrawn from the cage. Moving-catch delatch mechanisms promote manufacturing economy by minimizing the number of parts. However, moving-catch latching mechanisms suffer from dependence upon the resilience or flexibility of the catch.
A moving-pin delatch mechanism delatches the pin from the catch by causing the pin to retract into the module housing in response to the pivoting motion of the bail so that the pin and catch do not interfere with each other when the module is withdrawn from the cage. Moving-pin delatch mechanisms do not depend upon flexibility of the catch and provide low frictional resistance between the pin and catch. However, prior moving-pin delatch mechanisms can be complex, involving a substantial number of moving parts, adversely impacting manufacturing economy.